The worst situation I have had regarding invasions is when they begin as my character is in the process of entering sleep mode. This has not happened a lot maybe 6 times over the course of 5000 hours, but it has happened and imo it should not happen, a player should not be able to be in a situation where they can do absolutely nothing while their base is under attack. The majority of times the trigger occurs as my character is in the process of laying down, but it has happened twice after that point, when darkness has descended.